To provide an active region having first and second diffusion layers positioned at both sides of a gate trench and a third diffusion layer formed on a bottom surface of the gate trench, first and second memory elements connected to the first and second diffusion layers, respectively, a bit line connected to the third diffusion layer, a first gate electrode that covers a first side surface of the gate trench via a gate dielectric film and forms a channel between the first diffusion layer and the third diffusion layer, and a second gate electrode that covers a second side surface of the gate trench via a gate dielectric film and forms a channel between the second diffusion layer and the third diffusion layer. According to the present invention, because separate transistors are formed on both side surfaces of a gate trench, two times of conventional integration can be achieved.